1. Field of the Invention
The present invention relates to an optical connector.
2. Background Art
Conventional mechanically transferable (MT) optical connectors (such as those defined in IEC 60874-16 or JIS C 5981) are known to be optical connectors in which connection is made by inserting and engaging an engaging pin in an engaging hole and positioning to make an end-to-end connection. In addition, multifiber push-on (MPO) optical connectors (such as those defined in IEC 61754-7 or JIS C 5982) are known to be optical connectors composed by using the MT optical connector as a ferrule and incorporating in a housing formed from plastic and so forth.
However, since the MT optical connectors typically employ a constitution in which a metal engaging pin is inserted and engaged in an engaging pin hole formed in a plastic ferrule, the engaging pin hole becomes worn due to retraction and insertion of the engaging pin, thereby resulting in the problem of this wear causing a decrease in positioning accuracy. Consequently, there is a need to prevent wear of the engaging pin hole so as to effectively prevent a decrease in positioning accuracy caused by wear of the engaging pin hole as well as the resulting problems such as an increase in connection loss.
In response to this need, a technique is known for suppressing wear of the engaging pin hole accompanying extraction and insertion of the engaging pin in which a hard sleeve comprised of a material having high hardness such as zirconia-based ceramics is installed in the engaging pin hole to serve as a lining.
In the case of installing a hard sleeve in the engaging pin hole, if the end of the hard sleeve protrudes from the connecting end surface of the optical connector, the ends of the hard sleeves collide with each other during end-to-end connection of two optical connectors, thereby resulting in the risk of impairment of the physical contact (PC) connection of the optical connectors.
Consequently, in Japanese Unexamined Patent Application, First Publication No. 8-278426, a method is disclosed for polishing the end surface of the hard sleeve using a diamond grinder having a diameter similar to that of the hard sleeve so as to regress the end surface of the hard sleeve farther back than the connecting end surfaces of the optical connectors. However, in the case of this method, since it is necessary to accurately align the diamond grinder at the location of the hard sleeve during polishing, this work is extremely difficult, thereby resulting in the risk of decreased yield. Moreover, since the hard sleeve has high hardness, considerable time is required for its polishing, thereby resulting in the problem of poor productivity.
In consideration of the problems, an object of the present invention is to provide an optical connector capable of preventing impairment of PC connection by the end of a hard sleeve during PC connection of optical connectors having a hard sleeve installed in their engaging pin holes.